alemaozinho:I tried them out and it wasnt for me,sorry but i havent seen any fish with a split fin yet,split fins should have been invented before the regular ones,its only marketing.Try a few differend models so that you be able to compare.peace
Hmmm.. Maybe you haven't seen any fish with split fins because they are so fast, they can leave before you see them.. How about a Dolphin fish... And for efficiency, try to move a whale through the water... there's a rough hydrodynamics job... and again - split fin technology.